On 5 August and 13 August 1970, NASA Administrator Thomas Paine dispatched letters on the future of the U.S. lunar program to the Lunar and Planetary Missions Board (LPMB) and the Space Science Board (SSB) of the National Academy of Sciences National Research Council. In his letters, he outlined three options for curtailing Project Apollo. Of these, the first (Option I) would cancel one Apollo mission, while the others would nix two. The options he described were in part aimed at avoiding a delay in the Skylab Program, which constituted a step toward Paine’s favorite 1970s NASA goal: a 12-man Earth-orbiting space station that would be staffed and resupplied using a fully reusable space shuttle. Members of the LPMB and the SSB held an urgent two-day meeting (15-16 August 1970) in Woods Hole, Massachusetts, to develop a response to Paine’s letters.

By the time the LPMB and SSB met, NASA had flown three manned lunar landing missions: Apollo 11 (16-24 July 1969), which landed off-target on Mare Tranquillitatis; Apollo 12 (14-24 November 1969), which landed close by the derelict Surveyor 3 automated lander on Oceanus Procellarum, thereby demonstrating the pinpoint landing capability essential for geologic traverse planning; and perilous Apollo 13 (11-17 April 1970), which suffered an oxygen tank explosion in its Command and Service Module (CSM) that scrubbed its planned landing at Fra Mauro. Of these, Apollo 11 and Apollo 12 were mainly engineering missions intended to prove the Apollo system, while Apollo 13 had been intended as the first science-focused mission. Paine had canceled one Apollo mission, Apollo 20, in January 1970 so that its Saturn V rocket could launch the Skylab Orbital Workshop into low-Earth orbit. That left six moon landings before the program concluded with Apollo 19.

The program meant to extend piloted lunar exploration deep into the 1970s, the Apollo Applications Program (AAP), had taken repeated funding hits since 1967, and so had abandoned its lunar ambitions, becoming the strictly Earth-orbital Skylab Program in February 1970. Some concepts proposed for AAP lunar missions – for example, three-day lunar surface stays and a manned roving vehicle – would find their way into Apollo before its end, but when Apollo ended, so would end piloted lunar exploration.

With the goal of a man on the moon by 1970 successfully attained, pressure had begun to build to cancel some or all of the remaining Apollo lunar missions. In the aftermath of the Apollo 13 accident, some policy-makers questioned the wisdom of continuing to place astronauts at risk. Apollo 11 had humbled the Soviets on the technological prestige front of the Cold War; future landings would do little to enhance prestige, they argued, but a single lost crew could erase much of what the U.S. had gained by being first on the moon.

In addition, President Richard Nixon’s Office of Management and Budget was eager to rein in Federal expenditures. By mid-1970, the United States was spending roughly the entire $25-billion cost of the Apollo Program every 10 weeks to wage war in Indochina. Though NASA’s budget had fallen to only about $4 billion in 1970, the agency still constituted a highly visible and thus highly vulnerable target for new cuts.

"In their joint response to Paine, dated 24 August 1970, LPMB chair John Findlay and SSB chair (and Nobel Laureate) Charles Townes reminded Paine that past scientific advisory boards – including one Townes had chaired, which prepared a January 1969 report for then-President-elect Nixon – had advised that NASA should continue manned lunar exploration throughout the 1970s, and that from 10 to 15 manned moon landings should be flown. They cited this when they refused to consider cutting more than one Apollo mission. The Townes Committee had, incidentally, expressly opposed Paine’s large Earth-orbiting station.

"Apollo, they told the NASA Administrator, was of the greatest scientific importance. They explained that “the Apollo missions do not simply represent the study of a specific small planet but rather form the keystone for a near term understanding of planetary evolution.”

In their joint response to Paine, dated 24 August 1970, LPMB chair John Findlay and SSB chair (and Nobel Laureate) Charles Townes reminded Paine that past scientific advisory boards – including one Townes had chaired, which prepared a January 1969 report for then-President-elect Nixon – had advised that NASA should continue manned lunar exploration throughout the 1970s, and that from 10 to 15 manned moon landings should be flown. They cited this when they refused to consider cutting more than one Apollo mission. The Townes Committee had, incidentally, expressly opposed Paine’s large Earth-orbiting station.

Apollo, they told the NASA Administrator, was of the greatest scientific importance. They explained that “the Apollo missions do not simply represent the study of a specific small planet but rather form the keystone for a near term understanding of planetary evolution.” They then wrote that

"We respect the serious fiscal and programmatic constraints…. However, it should be recognized that any reduction in the number of missions will seriously threaten the ability of the total Apollo program to answer first-order scientific questions. We are on the very beginning of a learning curve, and it is clear that the loss of one mission will have much greater than a proportional effect on the instrumented experiments and, more critically, on the design and execution of the geology experiments involving the astronauts."

Findlay and Townes explained that at Woods Hole the LPMB and SSB had considered three options for Apollo’s future, all different from Paine’s three options. Option I was to fly missions 14, 15, 16, and 17 about six months apart, fly missions to the Skylab A Orbital Workshop over a period of about 20 months, and then carry out Apollo missions 18 and 19 six months apart.

Missions 14 and 15 would be H-class walking missions, as had been 12 and 13; 16 and subsequent would be J-class missions. The latter would include a Lunar Module (LM) capable of increased lunar surface stay time, a rover, improved lunar surface experiments, remote sensors on the CSM in lunar orbit, and a CSM-released lunar subsatellite. The long gap between Apollo 17 and 18 would permit lunar scientists to digest data from the previous missions and to design new experiments for the final mission pair. Findlay and Townes noted, however, that the gap might also make Apollo 18 and 19 vulnerable to budget cuts. Paine’s Option I had cut Apollo 15 and flown all the remaining lunar missions before Skylab A.

The LPMB and SSB’s Option II was to cut Apollo 15, fly 14, 16, 17, 18, and 19 about six months apart, and then fly the Skylab A missions. Their Option III was to cut Apollo 15, fly 14, 16, 17, 18, and 19 five months apart, and then fly Skylab A. Paine’s Options II and III had both omitted 15 and 19.

As might be expected, the LPMB and SSB favored their Option I, which cut no missions. If, on the other hand, “retreat from Option I proves unavoidable,” they recommended their Option III. This would, they explained, sacrifice Apollo 15 to save Apollo 19, which, they explained, would include 20% of the Apollo program’s moonwalk time and cover 25% of the total area to be included in Apollo traverses. In addition, by reducing the time between launches, they hoped to limit the costly delay in Skylab A’s launch.

They conceded that most of the experiments planned for Apollo could be carried out even if both Apollo 15 and 19 were cut. However, an automated station in the passive seismic network would be lost, surface samples would not be obtained from two geologically significant locations, and several experiments would be flown only once, so would have no backup. They concluded by reiterating that the cuts Paine envisioned could prevent lunar scientists from answering first-order questions about the moon, and added that “the consequences of such failure for the future of [NASA] and, we believe, for large-scale science in this country are incalculable.”